<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script type="text/javascript" src="./js/ctx.js"></script>
</head>
<body>
<div id="cesiumContainer">
</div>
<script>
    var initCesium = new InitCesium();
    var viewer =initCesium.initViewer('cesiumContainer', {
    });
    var layers= viewer.scene.imageryLayers;
    layers.addImageryProvider(Cesium.createOpenStreetMapImageryProvider({
        url : 'https://a.tile.openstreetmap.org/'
    }));
</script>
</body>
</html>